1. Field of the Invention
This invention relates to a differential pressure forming machine and more particularly to fluid pressure operated apparatus for mounting a differential pressure mold for movement with, and relative to, a vertically movable, mold mounting platen.
2. Description of the Prior Art
Differential pressure forming machines, are disclosed in U.S. Pat. No. 3,346,923, issued to G. W. Brown et al on Oct. 17, 1967, and U.S. Pat. No. 3,496,257, issued to G. W. Brown et al on Feb. 17, 1970, which are fully incorporated herein by reference as though fully recited word-for-word herein. These differential pressure forming machines include a pair of differential pressure molds which are vertically moved between spaced apart positions and closed, adjacent positions abutting opposite sides of a thermoplastic sheet of material at a forming station to differentially pressure form an object therein. In U.S. Pat. No. 3,868,209 issued to George H. Howell on Feb. 25, 1975, which is incorporated herein by reference, a thermoforming machine of the type described is disclosed wherein the upper and lower platens are locked in a closed position and thereafter expandable air bladders are provided on the lower platen to raise the lower mold relative to the lower platen toward the upper mold to tightly squeeze a thermoplastic sheet therebetween.
It is also known to mount a mold on a platen via a plate which is separated from the platen by a small gap in which a circumferentially disposed seal is disposed in sealing engagement with the mold mounting plate and the platen. The seal is compressible but the range of relative movement between the mold and platen is restricted. Accordingly, it is an object of the present invention to provide a new and novel apparatus for mounting a differential pressure mold on a platen.
It is another object of the present invention to provide new and novel fluid pressure operated apparatus for mounting a differential pressure mold on a platen.
A further object of the present invention is to provide new and novel apparatus of the type described for mounting a mold on a platen with double the stroke capacity.
A further object of the present invention is to provide fluid pressure operated apparatus for mounting a differential pressure mold on a platen by means of an expansible and contractible, fluid pressure operated chamber comprising an intermediate plate disposed between a plate which is mounted on the platen and a plate which mounts the mold, and disposing a seal between the intermediate plate and each of the tool mounting plate and the platen mounting plate.
Other objects and advantages of the present invention will become apparent to those of ordinary skill in the art as the description thereof proceeds.